Trihexyl phosphate to trihexyl phosphine oxide: Diverse effect on extraction behavior of actinides

Annam, Suresh; Gopakumar, Gopinadhanpillai; Rao, C. V. S. Brahmmananda; Sivaraman, N.; Sivaramakrishna, Akella; Vijayakrishna, Kari

doi:10.1016/j.molliq.2018.02.063

Cited by 22 publications

(9 citation statements)

References 44 publications

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Section: Resultssupporting

confidence: 82%

“…As one of the constituents of DES is TOPO, which is basic in nature, there is a possibility to take up the acid when in contact with acidic aqueous phase during extraction. The similar extraction of acids was observed by trihexyl phosphine oxide ligand as reported by Vijayakrishna et al [23] Hence, it is imperative to study the acid uptake behavior of synthesized DES. For this purpose, DES is equilibrated with different aqueous solution having different concentration of acid (HNO 3 ) ranging from 0.5 M to 6 M. The acid uptake values of DES are shown in the Table 1.…”

Section: Acid Uptake Study Of Synthesized Dessupporting

confidence: 78%

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A Hydrophobic Deep Eutectic Solvent for Nuclear Fuel Cycle: Extraction of Actinides and Dissolution of Uranium Oxide

Gamare,

Vats

2023

Eur J Inorg Chem

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Hydrophobic Deep Eutectic Solvents (DESs) have been attracting attention for metal ion extraction in solvent extraction process due to their favorable properties. A Trioctyl phosphine oxide (TOPO) and Thenoyl trifluoroacetone (HTTA) based hydrophobic DES was synthesized and characterized by FTIR and NMR spectroscopy. Actinide ions ( UO22+, Pu4+ and Am3+ ) and Eu3+ extraction was carried out using the DES which shows that it extracts these metal ions from aqueous nitric acid medium depending upon the molarity of nitric acid. At higher molarity of nitric acid (>5 M) the extraction becomes insignificant only for trivalent metal ions and open up the possibility to selectively strip trivalent metal ions from tetravalent and hexavalent ions. This DES was also used for dissolution of uranium oxide (UO3). The dissolution kinetics was studied and it was shown that oxide was dissolved within an hour at 80°C. The maximum solubility of UO3 in DES was measured and found to be 130±5 mg/mL which is one of the highest reported solubility of UO3 in ILs and DES. The species of uranium which is formed insitu in DES was ascertained to be UO2(TTA)2.TOPO after dissolution of UO3 as supported by FTIR and NMR (1H and 31P) investigations.

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Section: Resultssupporting

confidence: 82%

Section: Acid Uptake Study Of Synthesized Dessupporting

confidence: 78%

A Hydrophobic Deep Eutectic Solvent for Nuclear Fuel Cycle: Extraction of Actinides and Dissolution of Uranium Oxide

Gamare,

Vats

2023

Eur J Inorg Chem

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“…Various possible starting geometries were generated by distributing ligands and nitrate anions around UO 2 2+ . During this step, the metal–ligand stoichiometry was considered to be 1:2 because the same was experimentally estimated for various uranyl nitrate complexes with phosphorus-based ligands. ,,− A straightforward geometry optimization and subsequent characterization of harmonic vibrational frequencies resulted in several local minima on the potential energy hypersurface of each complex. The lowest-energy structures of uranyl nitrate complexes with various substituted phosphinic acid ligands are represented in Figure .…”

Section: Resultsmentioning

confidence: 99%

Insights into the Coordination Behavior of Methyl-Substituted Phosphinic Acids with Actinides

et al. 2022

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The electronic structure and complexation behavior of methylsubstituted phosphinic acids with U(VI) and Pu(IV) were explored by applying quantum chemical methods. In contrast to Ingold's classification, our results indicate that the methyl group is electron-withdrawing, reducing the phosphoryl group electron density in substituted phosphinic acids. The magnitude of the computed complexation energy values increases along with the series, PA → MPA → DMPA, and MP → MMP → MDMP, implying an increasing complexation tendency upon methyl group substitution for both U(VI) and Pu(IV) complexes. One of the nitrate groups in UO 2 (NO 3 ) 2 •2L complexes (L = PA, MPA, and DMPA) is in monodentate coordination mode due to the additional stability gained from O 2 N−O•••H hydrogen bonding interactions with the acidic H atoms of respective ligands. The calculation indicates marginally stronger metal−ligand interactions in Pu(IV) complexes compared to that in U(VI), which is supported by the computed complexation energies, M−O P bond lengths, ν(P�O), the extent of metal−ligand charge transfer, and properties of M−O P bond critical points. The energy landscape of substituted phosphinic acid ligands is further analyzed within the framework of the activation strain model to explain the energetic preference of certain conformers.

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“…The starting geometries were constructed by distributing the ligand molecule around metal nitrate in various possible orientations. This methodology was proven to be effective in the past for identifying the lowest-energy geometries of various actinide metal complexes. − The metal–ligand stoichiometry was considered to be 1:2 as it is the same stoichiometry experimentally estimated for uranyl nitrate complexes with various phosphate and phosphonate ligands (dibutyl phenyl phosphonate (DBPP), TBP, TAP, TiAP, etc. ). , The DFT-derived geometries of the four metal complexes are illustrated in Figure a–d.…”

Section: Results and Discussionmentioning

confidence: 99%

On the Nature of the Carbonyl versus Phosphoryl Binding in Uranyl Nitrate Complexes

et al. 2020

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The electronic structure of ligands with phosphoryl and carbonyl binding sites and their complexation behavior with uranyl nitrate were investigated using density functional theory (DFT). The quantum chemical calculations indicate that the electronic charges on both phosphoryl and carbonyl groups are more polarized toward oxygen atoms in isolated ligands. This effect is predominant in the case of complexes of the former. Both PO and CO groups are positively charged with the exception in methylisobutylketone (MIBK), where the C=O group is virtually neutral. The fragment molecular orbital analysis suggests that during complexation, a certain amount of charge transfer occurs from the filled pπ-orbitals [π x (CO/PO) and π y (CO/PO) ] of the ligand to 5f, 6d, and 7s orbitals of the uranium atom (fσ* and dsσ*). The NBO analysis reaffirms the charge transfer mechanism. The observed red shift in ν(CO) and ν(PO) identified in the simulated infrared spectrum of the corresponding complexes implies a moderate weakening of both carbonyl and phosphoryl bonds upon complexation. The atoms in molecules (AIM) analysis suggests a stronger phosphoryl binding compared to carbonyl interactions and an ionic U–O bond. The estimated complexation energies are considerable for phosphoryl ligands compared to those of the carbonyl analogue, with a reasonably large value derived for tri-n-butyl phosphate (TBP). The energy decomposition analysis marked significant stabilizing orbital interactions for phosphoryl ligands. The contributions of estimated dispersion energies are considerable in all complexes and extensively depend on the alkyl unit.

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Trihexyl phosphate to trihexyl phosphine oxide: Diverse effect on extraction behavior of actinides

Cited by 22 publications

References 44 publications

A Hydrophobic Deep Eutectic Solvent for Nuclear Fuel Cycle: Extraction of Actinides and Dissolution of Uranium Oxide

A Hydrophobic Deep Eutectic Solvent for Nuclear Fuel Cycle: Extraction of Actinides and Dissolution of Uranium Oxide

Insights into the Coordination Behavior of Methyl-Substituted Phosphinic Acids with Actinides

On the Nature of the Carbonyl versus Phosphoryl Binding in Uranyl Nitrate Complexes

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